Do VAV boxes have reheat coils?
The VAV concept may vary according to the VAV box locations, air temperature controls and types of heating elements. Heating can usually be provided by use of reheat coils or thermostatic baseboard. The unit contains a single heating coil which can be edited to change the type to 1-Water, 2-Electric or 3-Gas.
Why is it necessary to put reheat coils in VAV boxes?
Variable air volume (VAV) with reheat systems provide conditioned air to each zone at a constant temperature, typically 55°F. The amount of air varies to match the heat gain from equipment, lights- exterior and people.
Do VAV boxes have coils?
Typically, a VAV box consists of a few simple parts: the damper, the controller/actuator, and perhaps a coil for heating and cooling via electricity or water pumps. As the air passes through these boxes the actuator modulates the damper position which allows different amounts of airflow into the zone.
What is the purpose of a reheat coil when dehumidifying?
Reheat for dehumidification is simply cooling the air with the air conditioner to pull out the moisture. But instead of throwing the heat outside, the reheat coil simply puts that heat back Into the original air stream. It forces an air conditioner to act like a poorly designed dehumidifier.
Does a heating coil dehumidify?
1. Removes moisture from the air via condensation, then utilizes a heating coil, either sourced by hot water or an electric reheat coil to raise the supply air temperature to lower the Relative Humidity of the air entering the spaces, drying the spaces out. 2.
Why heating coil is used in Ahu?
It is also possible that a secondary heating coil in the AHU is located in the downstream side of the supply fan or cooling coil. The purpose of this secondary heating coil is to add additional heat to the air stream in cold climate zones, or climate zones where de- humidification is required.
What is the purpose of reheat coils?
What’s a reheat coil?
1. In an air-conditioning system, a coil which heats air in the supply duct to control its temperature. 2. A coil which is heated to control the temperature of air being furnished to individual zones, 1.
What removes moisture through ventilation?
In such cases, ventilation brings in humidity, and humidity is usually removed by air-conditioning (condensation on a cooling coil).
How do reheat coils work?
What is preheat coil in AHU?
Preheat and heating coils are typically located between the outside-air (OSA) intake and the cooling coil to protect the cooling coil from freezing conditions. This applies to both draw-through and blow-through configurations.
Where are reheat coils located?
The secondary heat exchanger or “reheat coil” is almost always located directly above the blower making them prone to collecting more dust and debris than air conditioning coils. This is why it is imperative to access, inspect and clean these coils in order to properly clean the system.